Acid-base regulation, as reflected by hydrogen ion concentration ([H+]), and the chemoreflex control of breathing were examined in healthy pre- (PRE; n=20) and postmenopausal (POST; n=15) women of a comparable age (45 ± 2.7 vs. 52 ± 1.8 years). [H+] behaviour was examined in both groups at rest and during exercise above the ventilatory threshold using Stewart’s physicochemical approach to acid-base analysis. Ventilatory chemoreflex characteristics were assessed using Duffin’s modified rebreathing protocol that includes 5 min of prior hyperventilation and maintenance of either hyperoxic (150 mmHg) or hypoxic (50 mmHg) iso-oxia. As expected, the ovarian hormones progesterone ([P4]) and estrogen ([E2]) were significantly lower in the POST group. [H+] was unaffected by menopausal status at rest or during exercise. At rest the POST group exhibited significantly higher PaCO2 and [SID] values relative to the PRE group. In general, the acidifying effects of increased PaCO2 were offset by the alkalizing effect of increases in [SID] (or vice versa) in the POST group such that [H+] did not differ between PRE and POST groups. The central ventilatory chemoreflex also differed between groups with the POST group exhibiting a significantly higher threshold and a lower sensitivity in the response to CO2 relative to the PRE group. [P4] was found to partially account for the significant group differences in acid-base and central ventilatory chemoreflex control characteristics supporting the role of [P4] as an important determinant of acid-base status and the chemical control of ventilation in healthy women. Findings of the current study may have potential relevance in understanding the increased occurrence of various health conditions such as osteoporosis and sleep disordered breathing in females following the onset of menopause. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2007-09-21 08:53:00.841

Human pregnancy is characterized by significant increases in central ventilatory drive and perceived respiratory discomfort (breathlessness). The physiological mechanisms of hyperventilation and breathlessness in pregnancy remain largely unknown and understudied. Objective: The main purpose of this research was to elucidate the mechanisms of maternal hyperventilation, and to systematically examine the contribution of alterations in central ventilatory drive, static/dynamic respiratory mechanics and their interaction with respect to the intensity of perceived breathlessness during exercise in pregnancy. General Methods: Experiments were conducted between 34-38 wks gestation and again 4-5 months post-partum in a total of 35 healthy, young women. A comprehensive mathematical model of ventilatory control was used to examine the role of alterations in wakefulness and central chemoreflex drives to breathe, acid-base balance and female sex hormones in maternal hyperventilation. The effects of pregnancy on detailed ventilatory (breathing pattern, airway function, operating lung volumes, esophageal pressure-derived indices of respiratory mechanics) and perceptual (breathing and leg discomfort) responses to incremental cycle exercise to the limits of tolerance were also examined. Results: Maternal hyperventilation resulted from a complex interaction between alterations in arterial and central acid-base balance and other factors that directly affect ventilation, including increased wakefulness and central chemoreflex drives to breathe, increased metabolism and decreased cerebral blood flow. Mechanical adaptations of the respiratory system, including recruitment of resting inspiratory capacity and reduced airway resistance, accommodated the increased demand for tidal volume expansion during exercise in pregnancy, while preserving effort-displacement and breathlessness-ventilation relationships. Variation in the severity of gestational breathlessness could not be explained by respiratory mechanical/muscular factors, but ultimately reflected variation in the amplitude of maternal hyperventilation and temporal desensitization to the sensory consequences of increased ventilation. Conclusion: Our results indicated that 1) the hyperventilation and attendant hypocapnia/alkalosis of pregnancy can be explained by alterations in wakefulness and central chemoreflex drives to breathe, acid-base balance, metabolic rate and cerebral blood flow; 2) mechanical adaptations of the respiratory system obviated the anticipated rise in perceived breathlessness for a given ventilation during exercise in pregnancy, and helped to ensure that peak aerobic working capacity was admirably preserved, even in late gestation; and 3) gestational breathlessness ultimately reflected the normal awareness of increased ventilation and contractile respiratory muscle effort. / Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2008-08-28 16:01:40.78

Experiments were conducted to investigate the effects of formulating rations using different ingredients and of manipulating the cation-anion balance of the rations on production, acid-base status, metabolism of macrominerals and renal function of dairy cows. The effects of dietary cation-anion balance were studied during early, mid and late lactation as well as during the dry period. Feeding an alfalfa-haylage based diet vs a corn silage based diet, both having the same cation-anion balance did not affect the voluntary consumption, milk yield or milk composition of cows in early lactation. The acid-base status of the animals was not affected by dietary treatment. The lower urinary bicarbonate concentration observed with the alfalfa haylage-based diet was not associated with a lower total urinary bicarbonate excretion since urine volume was significantly higher than when cows were fed the corn silage-based diet. Manipulating dietary cation-anion balance, however, resulted in changes in acid-base status at all stages of lactation studied. Urinary bicarbonate concentration and total daily excretion were increased by a higher dietary cation-anion balance at all stages of lactation. Similar effects of dietary cation-anion balance on urinary bicarbonate did not, however, translate into similar changes in production or intake by cows at differing stages of lactation. Cows in early and mid lactation seemed to have benefited more from a highly positive dietary cation-anion balance than cows in late lactation or dry period.

Relative changes are detectable in the blood of end-stage renal disease (ESRD) patients during hemodialysis (HD) treatment using optical spectroscopy. However, the potential impacts of several confounding factors that could affect the detection of these changes have not been evaluated. The objectives of this thesis were to: 1) investigate how the variations and/or changes in acid-base and oxygen parameters during HD treatment can affect the optical signature of whole blood of ESRD patients, 2) to investigate the effect of heparin on the optical properties of whole blood and its impact on our method. Blood samples were drawn from 23 ESRD patients at 5 time points during a 4 hour HD treatment and sent for blood gas and blood spectroscopy analyses. No significant correlations were found between the changes in the blood transmittance spectra and acid-base and oxygen parameters. This indicates that the perturbations in these parameters due to HD procedures do not confound the detection of changes in the blood transmittance spectra of ESRD patients during HD treatment. Additionally, the effect of heparin in modifying the optical properties of whole blood does not confound the detection of changes in the blood of ESRD patients due to HD treatment using whole blood-based optical spectroscopy. ANOVA revealed significant (P<0.05) measurable changes in the blood transmittance spectra of ESRD patients during HD treatment. Significant spectral differences (P<0.05) were found between ESRD patients. The lack of uniform spectral characteristics across patients is

The study of catalysis is a fundamental aspect of chemical engineering, as its implications affect all chemical transformations. Traditionally, catalysis has been subdivided into two areas: homogeneous and heterogeneous catalysis. Homogeneous catalysis refers to single-sited catalysts that exist in the same phase as the reaction media. These catalysts tend to be highly active and selective but often difficult to recover and reuse. In contrast, heterogeneous catalysts are typically multi-sited catalysts that exist in a different phase from the reaction media. These catalysts tend to be less active and selective than their homogeneous counterparts. However, the vast majority of industrial scale catalysts are heterogeneous because they can be easily separated, making them easily implemented in continuous processes, allowing for efficient, large scale operations. Due to the limitations of traditional homogeneous and heterogeneous catalysts, researchers have increasingly investigated hybrid catalysts that incorporate aspects of homogeneous and heterogeneous catalysis. This is accomplished via immobilization of homogeneous catalyst analogues onto solid-phase supports, thereby preserving the activity and selectivity of homogeneous catalysts while allowing for facile recovery and reuse from the insoluble, heterogeneous support. A variety of systems is presented here including organic and organometallic catalysts immobilized on organic and inorganic supports. Five cases are included. The first discusses utilization of supported acid and base catalysts for use in one-pot cascade reactions. The second example illustrates use of silica-coated magnetic nanoparticle supported acid catalysts for organic transformations. The third case presents novel polymer brush supported Cobalt-salen catalysts for the enantioselective, hydrolytic kinetic resolution of epoxides. A fourth case presents novel, magnetic polymer brush supported organic and organometallic catalysts for organic transformations. The fifth example illustrates polymer and silica supported ruthenium-salen catalysts for the asymmetric cyclopropanation of olefins. The overall goal of this thesis work is to develop novel supports and immobilization techniques to advance the field of hybrid organic/inorganic catalysts for the production of fine chemical and pharmaceutical intermediates.

The release of toxic metal species is of concern due to their detrimental effects on the environment and human health. Industrial effluents are a major source of mobilised metal species. Suitable technologies are needed to sequester toxic metal species at the point of source. Biosorption, which is based on the passive adsorption of contaminants onto biological materials, promises to offer an effective alternative or complementary step to existing treatment methods. However, to date there has been no widespread commercialisation of the technique. This is partly due to an insufficient understanding of the complex underlying mechanisms which makes it difficult to select suitable biomass for specific remediation problems and to predict process performance. This study characterised two gram-positive, thermophilic bacteria, Anoxybacillus flavithermus (BF) and Geobacillus stearothermophilus (BS), harvested at two different growth times, with regard to their acid-base and Cd�⁺ adsorption behaviour. The aim was to investigate the metal cation adsorption properties of thermophilic bacteria which has not been studied previously, and to gain a better understanding of the interactions responsible for bacterial metal cation adsorption. Experimental techniques employed in this study included microscopy to establish cell and cell wall morphology, batch acid-base and Cd�⁺ adsorption experiments to quantify proton active surface functional groups and Cd�⁺ adsorption, electrophoretic mobility measurements to assess the overall surface charge of the bacteria and in situ attenuated total reflection infrared (ATR-IR) spectroscopy to reveal the chemical identities of functional groups. Chemical equilibrium models based on batch acid-base titration and electrophoretic mobility data were developed to quantitatively describe proton active surface functional groups. These groups can also interact with metal cations. It was found that growth time was an important factor in all experiments with the differences between growth times often being more pronounced than the differences between the two bacterial strains. Microscopy revealed a gram-positive cell wall structure with different widths and staining behaviour for exponential phase cells of BF and BS. Stationary / death phase cells showed disintegrating cell walls. Acid-base titrations indicated that all cells possessed buffering capacity over the whole investigated pH range (pH 2 - 10). From electrophoretic mobility measurements, isoelectric points of ~ 3.2 for BF and < 1.8 and ~ 4.2 for exponential and stationary / death phase cells of BS respectively were estimated. Chemical equilibrium models including a Donnan electrostatic model were derived which described both the batch acid-base titration data and the electrophoretic mobility data reasonably well, although a comparison with IR data suggested room for further improvement. In situ ATR-IR spectroscopy of hydrated bacterial cells at various pH values revealed amide and carboxyl groups and a contribution from phosphate / polysaccharide moieties. Group specific interactions with Cd�⁺ were not detected, however, a partially reversible absorbance increase of all peaks suggested conformational changes in the presence of Cd�⁺. BF and BS adsorbed ~ 70 [mu]mol Cd�⁺ (g dry bacterial)⁻� at pH 5 in 0.01 M NaNO₃. Release of major cations occurred concomitantly with Cd�⁺ adsorption. The buffering and Cd�⁺-binding capacities of BF and BS were found to be comparable to those of mesophilic bacteria and ion exchange was identified as an important adsorption mechanism.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 267-277). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2006. / Michael Bergin, Committee Member ; E. Michael Perdue, Committee Chair ; Ching-Hua Huang, Committee Member ; Ellery Ingall, Committee Member ; Martial Taillefert, Committee Member. Vita. Includes bibliographical references.

Thesis (Ph. D.)--Miami University, Dept. of Chemistry and Biochemistry, 2004. / Title from second page of PDF document. Includes bibliographical references.